Improvement in doors for furnaces



L. MOKELVEY. Door for Furnaces.

No. 222,068. Patented Nov. 25, 1879.

Wmsses.

25,6. 12M/fj xwemom.

'UNITED STATES PME Ferron;

Y LEWIS McKELvnv, or PrrrsBURe, rnivNsYLvANIA.

IMPROVEMENT `IN DooRsFoR FU'RNACES. l

i Specification forming part of Letters` Patent No. `222,06S, dated November 25, 1879, application filed To all whom it may concern:

Be it knownthat I, LEWIS MCKELVEY, of the city of Pittsburg, in the county of Alle gheny Vand State `of ,Pennsylvanimhave invented a new and useful Improvement in Doors for Furnaces; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had` to the accom panyin g drawings, forming part of this specification, in which-- Figure 1 is a perspective view of my invention. Figs. 2 and 3 are detached views of the same.

My invention relates to furnace-doors, and is designed to overcome the loss arising from the rapid burning away of the door, especially in puddling and heating furnaces, but itis applicable to all descriptions of furnaces, and especially to those iu which the door is subjected to a greater degree of heat in one part than in another.

In the caseofthe doors of paddling-furnaces, which ordinarily weigh from one hundred and sixty-live to th ree hundred pounds, of iron casting, the lower part of the door is exposed to a muchmore intense heat than the upper part, and the saine is the case in heating-furnaces, where the weight of the doors runs from one hundred and fifty to six hundred pounds. In such furnaces, although they are lined with fire-brick, the lower part will frequently burn away in a few weeks, while the upper portion will remain good and will last formany years; but as the entire door becomes ruined and worthless where any portion of the iron is burned through a great loss and waste is the consequence. These doorsare, of course, subjected to the greatest heat at or near the bottom, or near thelevel of the hearth; but the destruction or burning out of the shell is found in practice to also extend up the sides to a greater or less extent, due probably to the access of air at the junction of thedoor and frame.

To remedy this difficulty I propose to build the iron part or shell of the door. in two or more pieces, the base piece or pieces being of general triangular form and extending up the sides along the line of greatest exposure, the several parts being liangedl and bolted together, as shown in the drawings, so that when A l f September 29, 1879. l

.the lower partburns away or .becomes so warped as to be no longer useful it may bere` moved, and its place supplied by a new piece or pieces. l

I willnow describe my invention, so that others skilled in the art may manufacture and use the same.4 p i The casing C of the door, which is iof the usual size and shape,`is made in two or more pieces, as shown in the drawings, which pieces dovetail together and are fastened by means of the lugs l, through `which pass the screwbolts Z), by which the several sections of the casing are rmly fastened together. These lugs l are placed in the inside of the casing G, between the brick-work, and are made with and form part of the casing. Each section'of the casing is furnished with two or moreof these lugs,.which are so arranged that the lugs of one section join and fit over the lugs .of the counter-section of the casing.

ln piuldling-furnaces I prefer to make the casing in four parts, as shown in the drawings, dividing it horizontally about half-way between the top and bottom of the door, and again at an angle running from the points a a, at the sides of the casing, a little more than onefourth the length ofthe door from the bottom thereof, downward, at about an angle of fortyiive degrees, to the points d d, thence horizontally across between these points, and also vertically from the points d d to the bottom of the door. This .divides the casing into four parts, and leaves a space, e, at the bottom, in which is fitted what is known as a. patent bit.77

In addition to the dovetailed edges of the casing and the lugs and screw-bolts `l and b, I use iron rods or standards j',wliich are attached to the lower sections of the casing, pass up along the edges of the casing on the inside, and are fastened to the upper flanges, as, of the top section of the casing by nuts or other device.

The casin g, being thus made in sections, is fastened firmly together by means of the lugs, screw-bolts, and standards, or other suitable devices, which may be used instead,` andthe brick-work is iilled in the usual way.

The upper section, 1, of the door will last from fifteen to twenty years, while the lower portions, 2, 3, and 4, will burn away in from six to eight weeks.

When one portion has been destroyed by the heat the fastening devices are unloosed, and the door taken to pieces and another portion substituted in its place.

It it is desired, the pieces 3 and 4 may be made in one piece instead of two, as shown in the drawings.

When the door to be -constructed is very wide it may be made in vertical sections, which are fastened `by standards and bolts passing horizontally across the door. The sections of the door may, if preferred, be filled in with brick-work separately, and there fastened together as hereinbefore described.

The lines of sections may be varied in different furnaces according to the extent of surface exposed to the greatest heat.

My invention is especially applicable to puddling and heating furnaces, but is also applicablev to ovens and other furnaces where the doors are exposed to irregular degrees 'of heat.

I am aware that furnace-doors have heretofore been formed in sections and with detachable base or bottom pieces, and therefore do not broadly claim the same; but,

Having thus `described my invention, what I claim, and desire to secure by Letters Patent, is-

1. In a sectional furnace-door, the combination, with one or more upper sections, of ade- 

